1. Field of the Invention
The present invention relates to the field of aero-lift-augmented airships and more particularly to such an airship deriving aerodynamic lift and speed via air flow through a variable geometry central venturi provided in an elongated annular airfoil hull or fuselage.
2. Brief Description of the Prior Art
Conventionally, lighter-than-air airships have been designed with elongated cigar-shaped hulls or fuselages enclosing buoyant gas-filled cells for lift and having engines for propulsion attached along the sides of the hull or fuselage, at the control compartment or at the stern of the airship. When this configuration of airship displaces a mass of air to the side due to its forward motion, the displaced air will eventually return near the stern of the airship exerting compressive force on the fuselage tail structure. This increased pressure requires a stronger and therefore a heavier supporting structure which results in increased weight and payload reduction.
Furthermore, some prior airships combine aerodynamic lifting with buoyant lifting in an attempt, primarily, to gain airspeed and improve payload capacity. Such aero-lift-augmented airships derive aerodynamic lift either integrally through high-lifting hull configurations or externally through the addition of special lifting surfaces or airfoils on an otherwise conventional appearing hull or fuselage.
However, such hybrid additions introduced increased structural weight as well as hull/lifting surface interference drag.
Therefore, a long standing need exists to provide a novel airship which gains airspeed and payload capacity by employing an augmented fuselage configuration without airfoil addition or increased propulsion on ordinary airship design.